docs: def is_null_like(x):
      """
      Determine whether an object is effectively null.
  
      :param object x: Object for which null likeness is to be determined.
      :return bool: Whether given object is effectively "null."
      """
      return x in [None, ""] or \
          (coll_like(x) and isinstance(x, Sized) and 0 == len(x))